This invention relates to surveillance of telephone calls over a public communications link and is particularly concerned with providing assistance for such surveillance to law enforcement agencies. It particularly concerns surveillance of voice of IP telephones transmitted over IP (i.e., cable) networks.
Requirements for enabling surveillance of electronic communications have been enacted into public law (e.g., Public Law 103-414 enacted Oct. 25, 1994; CALEA Communications Assistance for Law Enforcement Act) reciting requirements for assuring law enforcement access to electronic communications. Such access is required to be in real time, have full time monitoring capabilities, simultaneous intercepts, and feature service descriptions. The requirements specifically include capacity requirements and function capability. It is incumbent upon communication carriers to provide such capability and capacity.
While initially limited in scope, at present, to certain communications technology it is almost assured that it will be extended to new communication technologies in the near future.
Surveillance of IP voice calls over a public communication IP link is achieved in accord with principals of the invention by a WatchDog program, associated with an Address Mapping Center translating IP phone numbers into IP addresses, that are connected to a head end hub connected in turn to a Hybrid Fiber Coax (HFC) link of IP phone users or to a backbone network carrying IP voice packets.
In the illustrative example a WatchDog program with the address-mapping center is used for translating IP phone numbers to IP destination addresses. The IP addressing monitor is an IP element operating as a checkpoint which maps a telephone number to an IP address where the IP call is to be delivered. It also always delivers a duplicated packet to the monitoring watchdog for surveillance.